The full SKOS specification allows capturing much of what we want to do, including i18n via the label system, loos hierarchical relations via skos:broader, and the concepts of skos:Collection to aggregate concepts.

Here's one that comes in useful for my current i18n project: Using the jEdit Highlight Plugin (and regular expressions) to highlight code that needs to be done (white), code already done (green), and code I don't need to concern myself with (dark blue).